I'm having a big problem with flash content. Any site, any browser. Crunchyroll, Youtube, even flash ads have this weird black border around all four sides. The border is painted on top of the content. In fullscreen flash player, the border area covers a lot of pixels and is extremely annoying. Disabling add-ons, plugins, flash hardware acceleration, etc. doesn't seem to help. I couldn't find any information through Google.

Has anyone run into this problem?

Only thing I can remember doing around the time this started was clicking on some Youtube thing that appeared at the top of my screen and asked to confirm going fullscreen. I clicked Yes out of reflex. But this might be a coincidence...

Repeating suspicions is neither help nor support though it could be called "feedback."

The obvious questions are how do I confirm it? and how do I fix it?

Flash had a recent update (11.2) that has been causing issues with our Flash Player.
If you can find out what version of Flash you have you could try downgrading to 11.1 to see if this resolves the issue.

Repeating suspicions is neither help nor support though it could be called "feedback."

The obvious questions are how do I confirm it? and how do I fix it?

If you had simply stated "any site", but not "any browser", the obvious solution would have been to uninstall and re-install Flash, but IE and Firefox do not use the same Flash executable, and Chrome has Flash built-in, making it appear that the problem is in a common Flash setting.

Assuming you are running Windows, did you try doing a System Restore to a point before the problem existed?

The youtube/fullscreen prompt I clicked on to really was a chrome/google thing. I found the fullscreen exception for www.youtube.com while digging through my chrome settings. That's the first time I've heard of a setting like this.

EDIT: uninstalling flash, rebooting, and installing 11,1,102,63 had no effect.

I would assume Adobe does keep some code in common when building plugins for various platforms/browsers and if that's true then it's possible for them to release multiple plugins with the same bug. However, a setting is more likely - no idea how to find it though.

The youtube/fullscreen prompt I clicked on to really was a chrome/google thing. I found the fullscreen exception for www.youtube.com while digging through my chrome settings. That's the first time I've heard of a setting like this.

EDIT: uninstalling flash, rebooting, and installing 11,1,102,63 had no effect.

As it happens in all browsers, I'm assuming just disabling / re-enabling the Flash Player in Chrome has no effect?

You've certainly got me baffled. This is the first I've heard of anyone having this issue.

The opt-in HTML5/webm stuff plays fine in any browser (with appropriate plugins installed), no weird black stuff covering the content. Flash is the only one with the issue, and it's any Flash content - ads, videos, menus.

EDIT:

I found and fixed the problem. 12.3 catalysts enable something called AMD Steady Video which has a default zoom setting of 95%. Disabling AMD Steady Video in the catalyst control center eliminated the weird black stuff covering the edges of Flash content. The driver code is supposed to scale (approximately) the center 95% of content but on my chipset has a weird bug that just blacks out the other 5%.

The blocky/pixelated issue people are having with fullscreen Flash playback looks suspiciously similar to what would happen with simple 95% upscaling. You might try disabling the AMD Steady Video to see if those problems disappear, too.

EDIT 2:

Sadly, even with the AMD Steady Video disabled, I still get the pixelated fullscreen issue. 480P on Bleach ep. 222, btw.

I found and fixed the problem. 12.3 catalysts enable something called AMD Steady Video which has a default zoom setting of 95%. Disabling AMD Steady Video in the catalyst control center eliminated the weird black stuff covering the edges of Flash content. The driver code is supposed to scale (approximately) the center 95% of content but on my chipset has a weird bug that just blacks out the other 5%.

The blocky/pixelated issue people are having with fullscreen Flash playback looks suspiciously similar to what would happen with simple 95% upscaling. You might try disabling the AMD Steady Video to see if those problems disappear, too.

I noted in the Catalyst Control Center (now renamed AMD Vision Engine Control Center on my system with Catalyst 12.3) there is a item listed as "Apply current video quality settings to Internet video" which is unchecked. You may want to verify that is unchecked on your system, as well.